Re: Free-body diagram Correction

["Bob Sciamanda" <trebor@velocity.net>]

First do the straight textbook problem of a car executing a banked
highway curve, showing that there is a preferred car speed which requires
no friction.  As others have said, the only forces on the car are then
its weight and the normal force of support (which is inward and upward).
The resultant of these is the needed horizontal centripetal force.  Then
simply observe that the banked highway curve is a section of a cone!

-Bob

Bob Sciamanda   trebor@velocity.net
Dept of Physics
Edinboro Univ of PA  http://www.velocity.net/~trebor
Edinboro, PA   (814)838-7185

-----Original Message-----
From: Yvon Jean <phys@ntl.sympatico.ca>
To: phys-l@atlantis.uwf.edu <phys-l@atlantis.uwf.edu>
Date: Monday, April 20, 1998 9:15 PM
Subject: Re: Free-body diagram Correction


> Sciamanda wrote:
> It matters not whether the cone is rotating;
> the object, however needs a specific velocity (equivalently,
> rotational speed).
>
> I tend to agree with him.  The normal force will be the same in both
> cases...but the students really have a hard time with this one. Please
> enlighten!